The Preparation And Photoelectric Applications Of N-doped Carbon Quantum Dots

As a new type in the nanocarbon family, carbon quantum dots(CQDs) exhibit many advantages, such as low cytoxicity, high chemical stability, easy-preparation, and environmental friendliness. Moreover, because of their strong and tunable fluorescence emission properties,nanostructured carbon materials have attracted more and more attention.In this paper, three aspects have been discussed as followings: 1) boronic acid functionalized N-doped carbon quantum dots as fluorescent probe for selective and sensitive glucose determination, 2) photo-sensitive N-doped carbon conjugates as vectors for photocatalytic CS2 production, 3) preparation of N-doped carbon quantum dots for higyly sensitive detection of dopamine by an electrochemical method.Nitrogen doped carbon quantum dots(NCQDs) with about 10 nm in diameter have been obtained by hydrothermal reaction from collagen. Because of their superiority of water dispersion, low toxicity and ease of functionlization, the NCQDs were designed as a glucose sensor after grafting by 3-aminophenylboronic(APBA)(APBA-NCQDs). The as-prepared APBA-NCQDs have the ability glucose sensitivity and selectivity from other saccharides via fluorescence(FL) quenching effect at physiological pH and at room temperature. APBA-NCQDs showed high sensitivity and specificity for glucose determination with a wide range from 1 m M to 14 mM. FL quenching mechanism of APBA-NCQDs was also investigated by adding an external quencher. The APBA-NCQDs-based platform was an environmentally friendly way to substitute inorganic quantum dots containing heavy metals which offer a facile and low cost detection method.The photo-sensitive conjugates by displacing 1, 1-dithiooxalate and o-tert-butyl-dithiooxalate on NCQDs through hydrogen bonds was prepared. It was highly sensitive in photocatalytic CS2 production due to the energy transfer and electron transfer between carbon and organic ligands. The key towards success was opening a new avenue for the cheap and rapid release of a potential therapeutic agent using carbon materials vectors.A simple electrochemical biosensor was developed based on an NCQDs modified glass carbon electrode(NCQDs/GCE). The modified electrode displayed a good linear and broad response for the detection of dopamine(DA). The as-prepared biosensor also exhibitedsatisfactory selectivity even with interference of ascorbic acid(AA) and uric acid(UA).Inorganic ions also had no effect on detecting DA.